1. Field of the Invention
The present invention relates to a power seat for an automobile, and particularly to an improvement of the power seat in which a seat cushion is adjustably moved in a vertical or fore-and-aft direction by means of driving force of an electric motor.
2. Description of Prior Art
In a power seat, a seat cushion is to be adjusted in its vertical position or forward/backward position by use of electric motors. Conventionally, the electric motors are arranged in such a manner as shown in FIG. 1 of the accompanying drawings. This is also suggested from the Japanese Laid-Open Patent Publication No. 63-11462, for instance.
In the FIG. 1, the electric motors used are the one designated at (109) for causing vertical movement of the forward portion of a seat cushion (not shown) and the other one at (102) for causing vertical movement of the rearward portion of the seat cushion In operation, the driving force of the first motor (109) is transmitted through a reduction gear (101') and transmission shaft (104') to a torque shaft (103) which is then rotated, causing two links (107)(107) to move vertically, so that the seat cushion fixed to the links (107)(107) is moved vertically. Thus, the forward portion of the seat cushion is adjusted its height. Likewise, from the second motor (102), its driving force is transmitted through a reduction gear (102') and transmission shaft (105) to a torque shaft (103), then, with the rotation of the torque shaft (103), two rearward links (108)(108) are moved vertically, so that the rearward portion of the seat cushion is adjusted its height. The two torque shafts (103)(104) are at their both ends supported by a pair of brackets (202)(202') in a rotatable manner. Designations (101)(101) denote a pair of slide rails each being composed of an upper rail (101a) and a lower (101b), the upper rail (101a) being slidably fitted in the lower rail (101b). The brackets (202)(202') are fixed on the upper rails (101a), respectively.
The above-constructed power seat, however, has been with such problem that the motors (101)(102) are disposed right beneath the seat cushion, creating an increase of the height of the seat cushion by the size of the motors (101)(102), as a result of which, the head level of an occupant on the seat cushion is higher and closer to the ceiling of the automobile, and the occupant feels depressed with such narrow cabin space.
In view of such drawback, the Japanese Laid-Open Patent Publication No. 63-17135 proposes disposing the motors on the floor of automobile, laterally of the seat cushion.
But, such motor arrangement is only suited at a rear seat side, not suited at a front seat side, in the automobile. The reason is that the motors at the lateral side of the seat cushion are exposed externally with the possibility of being damaged by the foot of an occupant, especially in the case of the door side. Further, even in case of the rear seat side, the motors require a greater number of fittings and special designs in order to be installed on the floor at that rear seat, thus still posing drawbacks technically and economically.